X-ray goniometers providing independent control of three rotary motions and one reciprocating motion

ABSTRACT

In an X-ray goniometer an apparatus comprising a specimen holder, a first motor to move the holder in a linear reciprocating path parallel to the specimen face exposed to the X-rays, a second motor to rotate said holder about an X-axis normal to said face and passing through the center of said specimen, a third motor to rotate said holder about a Y-axis normal to said X-axis and lying in the plane defined by the incident and diffracted X-rays and a fourth motor to rotate said holder about a Z-axis normal to said plane and passing through said specimen; all four motors are adapted to be controlled independently of one another.

United States Patent [72] Inventor Kurt Luecke Morillenhang 80, 51Aachen, Germany 211 Appl. No. 749,425 [22] Filed Aug. 1, 1968 [45]Patented Feb. 23, 1971 [32] Priority Aug. 5, 1967 [33] Germany [31] P 1572 719.2

[54] X-RAY GONIOMETERS PROVIDING INDEPENDENT CONTROL OF THREE ROTARYMOTIONS AND ONE RECIPROCATING MOTION 9 Claims, 5 Drawing Figs.

[52] U.S.C| 250/51.5 [51] Int. Cl G01n 23/20; H01 j37/20 [50] FieldofSearch 250/51.5

[56] References Cited UNITED STATES PATENTS 2,559,972 7/1951 Kirkpatrick250/5l.5

1 1 14 ll|h "I" l" 7 'll h In r ll I v 1' 7 l I 5 l 2,798,957 7/1957Holden et al. 250/51.5 3,189,741 6/1965 Patser 250/51.5 OTHER REFERENCESPrimary Examiner-Archie R. Borchelt Assistant Examiner--C. E. ChurchAttorneyEdwin E. Greigg ABSTRACT: In an X-ray goniometer an apparatuscomprising a specimen holder, a first motor to move the holder in alinear reciprocating path parallel to the specimen face exposed to theX-rays, a second motor to rotate said holder about an X- axis normal tosaid face and passing through the center of said specimen, a third motorto rotate said holder about a Y-axis normal to said X-axis and lying inthe plane defined by the incident and diffracted X-rays and a fourthmotor to rotate said holder about a Z-axis normal to said plane andpassing through said specimen; all four motors are adapted to becontrolled independently of one another.

n" lll 27 5 20 X-RAY GONIOMETERS PROVIDING INDEPENDENT CONTROL OF THREEROTARY MOTIONS AND ONE RECIPROCATING MOTION BACKGROUND OF THE INVENTIONThe invention relates to an apparatus for the rapid determination of thecomplete polar configuration of the texture of crystalline specimens bymeans of measuring both the reflected and transmitted X-rays diffractedby certain crystallattice planes of the specimens.

Apparatuses for the determination of the directions of X- rays scatteredby aspecimen for the purpose of determining its texture are known in theart. In simpler devices of this type the specimen face scanned by theX-ray has a dimension identical to that of the image of the X-ray formedon the specimen. In more elaborate apparatus, the specimen is submittedto a reciprocating motion parallel with the plane of the specimen forthe purpose of scanning a larger specimen face than the image of theX-ray beam on the specimen. In general, during this reciprocating motioneffected by means of suitable mechanical devices, the specimen is, aftereach stroke, rotated through a small angle about an axis normal to theface of the specimen and passing through the center thereof. This axiswill hereinafter be denoted as axis .X. The specimen is also rotatedabout another axis (hereinafter referred to as axis Y) which is normalto the axis X and lies in a plane defined by the incident and diffractedX-ray. If the rotation about axis Y is performed slowly simultaneouslywith the azimuthal rotation about axis X, a spiral scanning of thespecimen results. If, on the other hand, the specimen is rotatedmanually or by means of a mechanical or electrical relay through apredetermined angle about axis Y only after each full azimuthalrotation, a scanning of the specimen in concentric azimuthal circlesresults. For the sensing of transmitted X-rays, the rotation about axisX is omitted and, instead, the specimen is rotated after each strokethrough a small angle about axis Y. In known X-ray goniometers after afull revolution of the specimen about axis Y, the specimen, iftransmitted X-rays are sensed, has to be rotated through a small anglecorresponding to the angle about axis Y for "the examination of thereflected rays -about an axis (hereinafter denoted as axis Z) which isnormal to the plane defined by the incident and diffracted X-rays andwhich passes through the specimen.

In known X-ray goniometers of this type the reciprocating motion and therotary motion about the three axes are all or in part connected to oneanother or they have to be effected manually so that an arbitrarycontrol of each individual motion or desired combinations thereof, e.g.,by means of a computer, is not possible due to the For the sensingprocess of transmitted X-rays -if this is at all possible -an additionalassistant is required for rotating the specimen about axis Z.

OBJECT AND SUMMARY OF THE INVENTION The. invention purports to avoid theaforenoted disadvantages in that the reciprocating motion and the rotarymotions about axes X, Y and Z may be controlled electrically,individually and independently of one another.

Briefly stated, according to the invention there is provided a firstmotor to move aspecimen holder in a linear reciprocating path, a secondmotor to rotate said holder about the aforedefined X-axis, a ringsurrounding said holder and having a normal axis coinciding with theafore-defined Y-axis, a third motor to rotate said ring and said holderas a unit about said Y-axis, a circular frame surrounding said ring andcontaining in its plane the afore-defined Z-axis, a fourth motor torotate said circular frame and said holder as a unit about said Z-axis.All four motors are adapted to be controlled independently of oneanother.

The invention will be better understood, as well as further objects andadvantages will become more apparent, from the ensuing detailedspecification taken in conjunction with the drawings.

structure of the goniometer. v

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF A PREFERRED EMBODIMENTFOR MOVING THE SPECIMEN Turning now to FIG. 1, there is shown a specimen1 fitted into a frame 2 which, in turn, is secured to a holder 3. Acarriage 4, to which holder 3 isaffixed, is mounted on a guide rail 5and is adapted to reciprocate thereon in the direction of arrow Wparallel with the specimen face directed outwardly from frame 2. Thelength of the strokes the carriage 4 may perform with thespecimen 1along guide rail 5 may be selected from between a zero value and adistance depending upon the dimensions of the apparatus. The aforenotedreciprocating motion is effected by means of a mechanism comprising amotor 6 which drives, through a shaft 7, an eccentric (not shown)disposed inside the carriage 4.

In known devices the scanning of the specimen 1 is performed in astarlike manner; that is, in different azimuthal positions differentareas of the specimen 1 are sensed. In the case of nonhomogeneoustextures or small specimens 1 which are often encountered in practice,such scanning results in erroneous measurements. This type of scanningprocess, however, is unavoidable in known apparatus since the carriage 4when executing the strokes indicated by arrow W has to follow therotational movement about axis X.

' According to the invention, on the other hand, at all times the samestriplike area of the specimen I is scanned. The angle of incidence ofthe X-ray R emitted by an X-ray tube (not shown) and adapted to scan thespecimen 1 remains constant with respect to axis Y. The assemblydescribed hereinbefore (the specimen holder, the motor 6, etc.) issurrounded and supported by a ring 8 which is rotatable about its normalaxis, coinciding with axis Y, by a motor 9 through a shaft 10, a wormgear 11, and a ring gear 12 disposed peripherally about ring 8.Simultaneously, the carriage 4 performs its rotational movements aboutaxis X by virtue of a motor 13 (also secured inside ring 8) driving agear 14 through a shaft 15 and a worm gear 16.

p The rotations about axis Z are effected by a motor 17 which, through ashaft 18 and a wormgear 19, rotates a. gear 20 secured to a circularframe 21. Within frame 21 there is disposed the ring 8 which, togetherwith the assembly supporting the specimen 1, may rotate with respect toframe 21 about axis Y and with frame 21 about a'xis Z. The latter liesin the plane of frame 21 and extends through the center thereof.

The motors 6, 9, 13 and 17 may be controlled independently of oneanother or may be coordinated in any combination by means of a computerto effect a programmed control of the reciprocating motion along arrow Wand the rotary motions about axes X, Y and'Z.

DESCRIPTION OF AN EXEMPLARY MODE OF OPERATION During a stroke in adirection along arrow W, rail 5 is rotated about axis X through 0.5 sothat for a full revolution of the guide rail 5 through 360 about axis X,720 strokes are executed. In order to avoid too rapid strokes, the motor6, driving the eccentric (not shown), is down-geared 2:l which meansthat the motor 13 rotating the guide rail 5 about axis X has to bedown-geared 720:1 since both motors 6 and I3 have to run synchronously.A cam (not shown) is secured to the guide rail 5 in such a manner thatafter a full revolution of the rail about axis X, the cam trips a relay(not shown) energizing the motor 9 to rotate ring 8 and specimen 1 as aunit about axis Y through The motor 9, too, is down-geared to a ratio720:1 since it assumes the function of the motor 13 when transmittedX-rays are observed. After a full revolution of the vertical ring 8about the axis Y, a cam (not shown) secured thereto actuates a contact(not shown) which starts the motor 17 for a 5 rotation of frame 21, ring8 and specimen 1 about axis Z.

APPARATUS FOR PREPARING THE SPECIMEN In order to take advantage of anoperating speed which is a multiple of that of known X-ray goniometers,the specimen 1 is, for the purpose of rendering it more rigid, deformedprior to placing it in the goniometer. For this purpose there isprovided, as shown in FIG. 2, a stamping device generally indicated at22. It comprises a U-shaped bracket 23 through the upper leg 24 of whichthere is guided. a punch 25 having a rectangular cross section. Underthe punch 25, secured to the lower leg 26 of the bracket 23 there isdisposed a die 27 in the inside of which there is contained a spring 28urging a base plate 29upward. The upper edges of the die 27 arechamfered as shown at-30. The end face of the punch 25 is similarlychamfered asshown at 31, from a central protrusion 32 which fits intothe opening of the die 27.

TWO EMBODIMENTS OF THESPECIMEN HOLDER Turning now to FIG. 3, thespecimen 1, deformed as shown in FIG. 2, is press fitted into frame 2and adjusted. The frame 2, the small sides of which are formed asguideedges 33 and .34, may be inserted into the U-shaped holder 3 whichitself is secured to the carriage 4. The inner faces 35 and 36 of thetwo opposed upstanding sides of the holder 3. are provided with a firstpair of parallel grooves 37, 38 and a second pair of parallel grooves39, 40 arranged normal to the first pair. The groove pairs 37,-38 and39, 40 are adapted to selectively receive the guide edges 33, 34 offrame'2. For measuring the X-rays transmitted by specimen 1, the frame 2is inserted into the groove pair 37, 38, while for sensing reflectedrays, the frame 2 is positioned in the groove pair 39, 40.

Referring now to FIGS. 4a and-4b, there is shown adevice generallyindicated at 41 which is another embodiment of the holder for thespecimen frame 2. The device 41 comprises a base plate 42 to which thereare secured two angle members 43 and 44. One leg of each angle member43, 44 extends normal to the base plate 42, while the respective otherlegs point in opposite directions with respect to one another and aresecured to base plate 42. The specimen holder 45 is rotatably mounted onthe upstanding legs of the angle members by means of stub shafts 46 and47 and may be immobilized by means of pin 48. The specimen frame 2 isinserted into the rectangular opening of the specimen holder 45. In theposition shown in FIG. 4a the device is set for measurements ofreflected X-rays, whereas in the positionshown in FIG. 4b thetransmitted rays may be sensed. In order to arrive from the formerposition to the latter, the pin 48 is withdrawn from the hole 49 whichis provided in a circular disc 50 fixedly secured to the specimen holder45; then the specimen holder is rotated and the pin 48 is inserted intoa second hole 51 in the disc I claim:

1. In an X-ray goniometer for determining the complete polarconfiguration of the texture of a crystalline specimen by sensing thereflected and transmitted X rays diffracted by certain crystal latticesof said specimen after impinging on one face thereof, the improvementcomprising:

A. a first means for imparting a linear reciprocating motion to saidspecimen parallel to said. face thereof;

B. a second means for imparting a rotation to said specimen solely aboutan X-axis normal to said face and through the center of said specimen;

' C. 'a third means for imparting a rotation to said specimen solelyabout a Y-axis normal to said X-axis and contained in a plane defined bythe impinging and diffracted X-rays; and

D. a fourth means for imparting a rotation of said specimen solely abouta Z-axis normal to said plane and lying on said face of said specimen,said first, second, third and fourth means being simultaneously operableindividually and independently of one another.

2. The improvement as defined in claim 1, wherein said first, second,third and fourth means each includes an independently controllablemotor.

3. The improvement as defined in'claim 2, including a ring surroundingand supporting said specimen, said first and said second means; saidring has a normal axis coinciding with said Y-axis; said ring and saidspecimen are rotatable as a unit about said Y-axis by virtue of saidmotor associated with said third means.

4. The improvement as defined in claim 3, including a circular frame;said Z-axis extends diametrically with respect to said frame and passesthrough the center thereof; said frame, said ring and said specimen arerotatable as a unit about said Z-axis by virtue of said motor associatedwith said fourth means.

5. The improvement as defined in claim 1, including a holder means forfixedly supporting said specimen during operation.

6. The improvement as defined in claim 5, wherein said holder meansincludes a frame directly engaging and holding said specimen and aholder receiving said frame with said specimen.

7. The improvement as defined in claim 6, wherein said holder includesmeans for selectively supporting said frame in either of two fixed,mutually perpendicular positions.

8. The improvement as defined in claim 7, wherein said holder includestwo parallel spaced inner faces each provided with two pairs of grooves,one pair of grooves is perpendicular to the other pair, the groovesforming a pair are parallel to one another and are provided on one ofeach inner face, said frame is selectively insertable into one or theother said pair of grooves.

9, The improvement as defined in claim 7, wherein said holder ispivotally supported by a base and means are provided to immobilize saidholder in either of said two, positions.

1. In an X-ray goniometer for determining the complete polarconfiguration of the texture of a crystalline specimen by sensing thereflected and transmitted X-rays diffracted by certain crystal latticesof said specimen after impinging on one face thereof, the improvementcomprising: A. a first means for imparting a linear reciprocating motionto said specimen parallel to said face thereof; B. a second means forimparting a rotation to said specimen solely about an X-axis normal tosaid face and through the center of said specimen; C. a third means forimparting a rotation to said specimen solely about a Y-axis normal tosaid X-axis and contained in a plane defined by the impinging anddiffracted X-rays; and D. a fourth means for imparting a rotation ofsaid specimen solely about a Z-axis normal to said plane and lying onsaid face of said specimen, said first, second, third and fourth meansbeing simultaneously operable individually and independently of oneanother.
 2. The improvement as defined in claim 1, wherein said first,second, third and fourth means each includes an independentlycontrollable motor.
 3. The improvement as defined in claim 2, includinga ring surrounding and supporting said specimen, said first and saidsecond means; said ring has a normal axis coinciding with said Y-axis;said ring and said specimen are rotatable as a unit about said Y-axis byvirtue of said motor associated with said third means.
 4. Theimprovement as defined in claim 3, including a circular frame; saidZ-axis extends diametrically with respect to said frame and passesthrough the center thereof; said frame, said ring and said specimen arerotatable as a unit about said Z-axis by virtue of said motor associatedwith said fourth means.
 5. The improvement as defined in claim 1,including a holder means for fixedly supporting said specimen duringoperation.
 6. The improvement as defined in claim 5, wherein said holdermeans includes a frame directly engaging and holding said specimen and aholder receiving said frame with said specimen.
 7. The improvement asdefined in claim 6, wherein said holder includes means for selectivelysupporting said frame in either of two fixed, mutually perpendicularpositions.
 8. The improvement as defined in claim 7, wherein said holderincludes two parallel spaced inner faces each provided with two pairs ofgrooves, one pair of grooves is perpendicular to the other pair, thegrooves forming a pair are parallel to one another and are provided onone of each inner face, said frame is selectively insertable into one orthe other said pair of grooves. 9, The improvement as defined in claim7, wherein said holder is pivotally supported by a base and means areprovided to immobilize said holder in either of said two positions.